One thing seems clear. Scientists are people, not rational automatons. They differ from other people in terms of what they do, in the things that give them satisfaction, more than in terms of completely special capacities. There is nothing you can say about them as persons that you cannot also say about some people who are not scientists. And there is almost nothing you can say about a man in some particular field of science that you cannot also say about someone in another field of science. In spite of this, there are patterns, patterns in their life histories, patterns of intellectual abilities, patterns of personality structure, which are more characteristic of scientists than they are of people at large, and some which are more characteristic of special kinds of scientists than of other scientists.

There are distinct patterns in these life histories. These scientists come from rather selected families, since half of them had fathers who were professional men, and none of them had fathers who were unskilled laborers. And none of them came from Catholic homes. This pattern is about the same in all of the groups, except that there is a higher proportion of professional fathers among the theoretical physicists, and a somewhat lower proportion among the experimental physicists.

Not all the sons of professional fathers become scientists, but this background more than others, seems to have a predisposing effect. Why? By and large the intelligence of people in professional occupations is relatively high, and so their children would be expected to be relatively bright, hence there may be some hereditary factor. But the inheritance of intelligence is a very complicated matter, and not too well understood, and I think here of relatively less importance than other things. What seems to be important in the home background is the knowledge of learning, and the value placed on it for its own sake, in terms of the enrichment of life, and not just for economic and social rewards. This high evaluation placed on learning and on intellectual satisfactions was also operative in many of the homes in which the father was not a professional man. The few scientists whose homes lacked this had always had close contact with some one else, usually a teacher, who held this attitude.

A love of knowledge for its own sake appears to be the most important factor.

4- As an example, consider the practice of mathematics. Mathematics is in the first place a language in which we discuss those parts of the real world which can be described by numbers or by similar relations of order. But with the workaday business of translating the facts into this language there naturally goes, in those who are good at it, a pleasure in the activity itself. They find the language richer than its bare content; what is translated comes to mean less to them than the logic and the style of saying it; and from these overtones grows mathematics as a literature in its own right. Mathe¬ matics in this sense, pure mathematics, is a form of poetry, which has the same relation to the prose of practical mathematics as poetry has to prose in any other language. This element of poetry, the delight in exploring the medium for its own sake, is an essential ingredient in the creative process.

They work the art as if it were poetry, much of it without practical application, but for the beauty of mathematics.